#include <stdio.h>

int max(int x, int y);

int main(void)
{
	extern int a, b;
	
	printf("max = %d\n", max(a, b));

	return 0;
}

int max(int x, int y)
{
	int z;
	
	z = x > y ? x : y;
	
	return z;
}

int a = 15, b = 8;